Acoustic wave devices are used in filters for mobile communications. There has been known an art that forms wiring lines that interconnect acoustic wave resonators formed on a substrate or connect the acoustic wave resonator to an external terminal so that the wiring lines intersect each other across an air gap as disclosed in Japanese Patent Application Publication No. 2012-9989. There has been known an art that forms an inductor above a substrate across an air gap as disclosed in Japanese Patent Application Publication Nos. 7-321425 and 2012-80016. There has been known an art that connects an inductor to a filter using an acoustic wave resonator as disclosed in Japanese Patent Application Publication Nos. 2001-285025 and 2004-112277.
To reduce the size of the acoustic wave device, the distance between the wiring lines interconnecting the acoustic wave resonators needs to be reduced. However, when the distance between the wiring lines interconnecting the acoustic wave resonators is reduced, the capacitance between the wiring lines increases. Thus, the downsizing of the acoustic wave device is not easy.